Joshua 4
6 Ref that this may be a sign among you, that when your children ask in time to come, saying, What do you mean by these stones?
7 Ref then you shall tell them, Because the waters of the Jordan were cut off before the ark of the covenant of Yahweh; when it passed over the Jordan, the waters of the Jordan were cut off: and these stones shall be for a memorial to the children of Israel forever.